Re: port-m68k/55990: kernel stack leak in m68k cpu_setmcontext() and reenter_syscall()

[Jason Thorpe <thorpej%me.com@localhost>]

The following reply was made to PR port-m68k/55990; it has been noted by GNATS.

From: Jason Thorpe <thorpej%me.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: port-m68k-maintainer%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost,
 netbsd-bugs%netbsd.org@localhost,
 tsutsui%ceres.dti.ne.jp@localhost
Subject: Re: port-m68k/55990: kernel stack leak in m68k cpu_setmcontext() and
 reenter_syscall()
Date: Mon, 22 Feb 2021 07:58:15 -0800

 > On Feb 21, 2021, at 4:40 AM, Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost> =
 wrote:
 >=20
 > With this patch, the Xorg based servers both on sun3 and x68k survive
 > over 24 hours without kernel crashes.
 > (Note the similar x68k crashes were observed at least back in 2012.)
 >=20
 > I wonder if we should also check frame->f_stackadj in trap0()
 > but I would like to commit this fix (workaround?) for now.
 >=20
 > Any comments (especially from m68k and siginfo gurus; kleink@? =
 thorpej@?)
 > are appreciated.
 
 I'm really digging into archival section of by brain for this one, but =
 this change seems perfectly reasonable.
 
 -- thorpej